Commit 8dd16f5e authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: add a bio_add_vmalloc helpers 



Add a helper to add a vmalloc region to a bio, abstracting away the
vmalloc addresses from the underlying pages and another one wrapping
it for the simple case where all data fits into a single bio.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250507120451.4000627-5-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 75f88659

block/bio.c

+55 −0
Original line number Diff line number Diff line
@@ -1076,6 +1076,61 @@ bool bio_add_folio(struct bio *bio, struct folio *folio, size_t len, 
}

EXPORT_SYMBOL(bio_add_folio);



/**

 * bio_add_vmalloc_chunk - add a vmalloc chunk to a bio

 * @bio: destination bio

 * @vaddr: vmalloc address to add

 * @len: total length in bytes of the data to add

 *

 * Add data starting at @vaddr to @bio and return how many bytes were added.

 * This may be less than the amount originally asked.  Returns 0 if no data

 * could be added to @bio.

 *

 * This helper calls flush_kernel_vmap_range() for the range added.  For reads

 * the caller still needs to manually call invalidate_kernel_vmap_range() in

 * the completion handler.

 */

unsigned int bio_add_vmalloc_chunk(struct bio *bio, void *vaddr, unsigned len)

{

	unsigned int offset = offset_in_page(vaddr);



	len = min(len, PAGE_SIZE - offset);

	if (bio_add_page(bio, vmalloc_to_page(vaddr), len, offset) < len)

		return 0;

	if (op_is_write(bio_op(bio)))

		flush_kernel_vmap_range(vaddr, len);

	return len;

}

EXPORT_SYMBOL_GPL(bio_add_vmalloc_chunk);



/**

 * bio_add_vmalloc - add a vmalloc region to a bio

 * @bio: destination bio

 * @vaddr: vmalloc address to add

 * @len: total length in bytes of the data to add

 *

 * Add data starting at @vaddr to @bio.  Return %true on success or %false if

 * @bio does not have enough space for the payload.

 *

 * This helper calls flush_kernel_vmap_range() for the range added.  For reads

 * the caller still needs to manually call invalidate_kernel_vmap_range() in

 * the completion handler.

 */

bool bio_add_vmalloc(struct bio *bio, void *vaddr, unsigned int len)

{

	do {

		unsigned int added = bio_add_vmalloc_chunk(bio, vaddr, len);



		if (!added)

			return false;

		vaddr += added;

		len -= added;

	} while (len);



	return true;

}

EXPORT_SYMBOL_GPL(bio_add_vmalloc);



void __bio_release_pages(struct bio *bio, bool mark_dirty)

{

	struct folio_iter fi;

include/linux/bio.h

+3 −0
Original line number Diff line number Diff line
@@ -433,6 +433,9 @@ static inline unsigned int bio_add_max_vecs(void *kaddr, unsigned int len) 
	return 1;

}



unsigned int bio_add_vmalloc_chunk(struct bio *bio, void *vaddr, unsigned len);

bool bio_add_vmalloc(struct bio *bio, void *vaddr, unsigned int len);



int submit_bio_wait(struct bio *bio);

int bdev_rw_virt(struct block_device *bdev, sector_t sector, void *data,

		size_t len, enum req_op op);